Added the following IPTC fields commonly used on Press photos:

* IPTC_KEYWORDS (Keywords)
* COPYRIGHT_NOTICE (CopyrightNotice)
* CREATOR (Creator)
* CAPTION_ABSTRACT (Caption-Abstract)
* OBJECT_NAME (ObjectName)
Merge pull request #16 from wiecklabs/feature/add-common-iptc-tags

Added the following IPTC fields commonly used on Press photos: